Solvation behaviour of some tetraalkylammonium ions in acetonitrile + dimethyl sulphoxide mixtures: Conductance and viscosity measurements at 25°C

Abstract

Precise values of conductance and viscosity of Et₄NBr, Pr₄NBr and Bu₄NBr have been measured in the concentration ranges (1-30) x 10^-4 and (20-200) x 10^-4 dm³ mol^-1, respectively, in acetonitrile (AN), dimethyl sulphoxide (DMSO) and AN + DMSO mixtures at 25°C. The conductance data have been analyzed by the Shed-lovsky conductance equation. The limiting ionic conductances (λ<img src='http://www.niscair.res.in/jinfo/equation127.gif' border=0>) for Et₄N⁺, Pr₄N⁺ and Bu₄N⁺ ions have been evaluated to calculate the solvated radii (<em>r</em>_i) and the ionic Walden product (λ <img src='http://www.niscair.res.in/jinfo/equation127.gif' border=0> η₀). The viscosity data have been analyzed by the Jones-Dole equation to evaluate A and B-coefficients. Ionic B₊ values for Et₄N⁺, Pr₄N⁺ and Bu₄N⁺ ions have been calculated from viscosity B-coefficients of the electrolytes and A-coefficients have been compared with theoretically calculated A_η- coefficients. The variation of <em>r</em>_i, B₊ and λ <img src='http://www.niscair.res.in/jinfo/equation127.gif' border=0> η₀values have been measured as a function of solvent composition to interpret the solvation pattern of tetraalkylammonium ions in AN + DMSO mixtures.